Clad in black leather and flanked by an army of military-clad dancers, the two powerhouse singers commanded the audience with a show-stealing rendition so big a wide-eyed Tyra Banks mouthed "That was so powerful" after they finished. They ended kneeling on stage, clutching one another's faces, as footage of young girls played behind them.

"I have always looked up to Christina. I remember being at her concert and singing facing the crowd instead of the stage, knowing that that was exactly what I wanted to do in life," previously toldBillboard of working with Aguilera. "She speaks up for what she believes in and sends a positive message, which are two things I find extremely important when given the platform we are lucky enough to have."

"Fall In Line" is the third single to come from Aguilera's forthcoming eighth studio album, Liberation, her first in six years. It follows the Kanye West-produced "Accelerate," featuring Ty Dolla $ign and 2 Chainz, and big-voiced power ballad "Twice," both released earlier this month.

Aguilera will hit the road in support of Liberation this fall, marking her first tour in a decade. The record is due out June 15.